Compilare: user.cpp: In function ‘void genHash()’: user.cpp:18:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < a.length(); i++) ^ user.cpp:25:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a.length(); i++) ^ user.cpp:37:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int dr = a.length(); dr < b.length(); dr++) ^ user.cpp: In function ‘int main()’: user.cpp:60:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a.length(); i++) ^